COMPARISON OF WATER CHEMISTRY OF STREAMS DRAINING DEFORESTED, REGROWTH, AND OLD GROWTH PORTIONS OF LAND IN THE SALMON LA SAC AREA, WASHINGTON STATE

Deforested, regrowth, and old growth sections of land in the Salmon la Sac area, in central Washington State, were studied to determine the effects of clear cutting on water quality. Stream water chemistry was analyzed using an Inductively Coupled Plasma Mass Spectrometer determining major and trace element concentrations. There was a general increase in the concentrations of both major and trace elements in those streams located in regrowth areas as compared to deforested and old growth areas. The most pronounced increases were those major elements Na, Ca, Mg and trace elements Ba, Sr, Al, and As. The high concentration of As was an unpredicted occurrence. It is hypothesized that the As levels may have come from the weathering of ultra-mafic rocks in the region or may have been caused by anthropogenic influences. Regrowth sections of land were replanted in the mid 1980's by private logging companies, high element concentrations in those streams was an unexpected result that suggests the effects of deforestation may sustain for relatively long periods of time (>15yrs).